The vast majority of temperature sensors used in industry and research are secondary thermometers. This means that the respective temperature sensors, which contain e.g. thermocouples or temperature-dependent resistances, need to be calibrated at least before their first use and in most cases also repeatedly during their service life. To this end, during the comparison process, the temperature sensors to be calibrated are compared with a standard thermometer in temperature stabilized ovens or baths. Portable devices, which bring a corresponding calibration volume to a specifiable constant nominal temperature, are known from the specification U.S. Pat. No. 3,939,687 A. In order to ensure an optimal thermal coupling of the devices under test with the calibration volume, various inserts, which are adapted to the temperature sensors to be tested or calibrated, can be introduced as solid bodies into the calibration volume of a temperature calibrator. These inserts largely fill up the calibration volume and feature recesses into which the temperature sensors to be calibrated can be inserted. In order to achieve a spatial temperature distribution within the calibration volume that is as constant as possible, the insert, in a dry-block temperature calibrator, respectively the calibration medium, in a temperature calibration bath, should have a thermal conductivity that is as high as possible.
In addition, a cooling and/or deep-freezing apparatus with a temperature sensor for detecting the temperature in one place of or of a component of the cooling and/or deep-freezing apparatus is known from DE 10 2010 010 618 A1. Here, the sensor has a magnetocaloric material or is at least partially comprised of such a material.
As another prior art, DE 11 2006 001 628 T5 describes a ferromagnetic shape-memory alloy, which is able to restore its shape. The shape restoration is accompanied by a magnetic change due to the magnetic-field-induced reconversion to a practical temperature range.
Since the calibration volume must be brought to the nominal temperature prescribed by the user, heat can be removed or added to the calibration volume, in which e.g. an insert with inserted temperature sensors is located, via a thermally conductive body, which surrounds the calibration volume. In portable calibrators, this thermally conductive body is typically implemented as a metal block and is in thermal contact with cooling units, such as e.g. Peltier elements, as described in DE 20 2005 006 710 U1, and heating units, such as e.g. a resistance heater.